In the 17th century, security was often a matter of mechanical ingenuity rather than the kinds of technology we rely on today such as cameras and alarm systems. If you wanted to keep someone out, you had to physically bar them, or devise a mechanism that would-be intruders couldn't solve.

This lock, wrought sometime around 1680, is currently on display in Rijksmuseum, a history and art museum in Amsterdam. It was crafted from brass and steel by a locksmith named John Wilkes-neither the famous member of British parliament nor the assassin of president Lincoln.

Just having the key to the lock is not enough to gain entrance. The elaborate lock contains multiple mechanisms that require proper manipulation to open. Triggering the soldier's hat will lock and unlock a secondary bolt, so the door could be locked even without the key, and only those who knew how to operate the device could unlock it.